Conceptual boundaries for monetary policy theory in XXI century: from blockchain to modern monetary theory

After mortgage crisis in 2007-2009 the world economies faced the lack of money problem that is depicted in lowering of broad money growth and increasing of general level of prices. This problem made monetary authorities to look for new solutions. The paper concerns theoretical analysis of two issues: blockchain as a concept for monetary policy development and modern monetary theory (MMT) postulates as systemic shift in theoretical and practical implementations of monetary policy in XXI century. These concepts are considered in comparison with macroeconomic mainstream. As an information technology blockchain can offer wide advantages for monetary policy to improve its functioning. Cryptocurrency as the main form of blockchain realization cannot be true rival for fiat money nowadays. MMT offers to print more money as an answer to economic problems. It does not concern issues of market discipline for financial intermediaries. For the blockchain system there exists no statewith its budget, taxes, social responsibilities, inflation regulation and so on. Therefore, the conclusion of the research is that the future monetary policy will have combined characteristics of these concepts.